new mapper helpers

backend/internal/data/repo/automappers.go

@@ -0,0 +1,32 @@
+package repo
+
+type MapFunc[T any, U any] func(T) U
+
+func (a MapFunc[T, U]) Map(v T) U {
+	return a(v)
+}
+
+func (a MapFunc[T, U]) MapEach(v []T) []U {
+	result := make([]U, len(v))
+	for i, item := range v {
+		result[i] = a(item)
+	}
+	return result
+}
+
+func (a MapFunc[T, U]) MapErr(v T, err error) (U, error) {
+	if err != nil {
+		var zero U
+		return zero, err
+	}
+
+	return a(v), nil
+}
+
+func (a MapFunc[T, U]) MapEachErr(v []T, err error) ([]U, error) {
+	if err != nil {
+		return nil, err
+	}
+
+	return a.MapEach(v), nil
+}